So what is happening here? Well firstly we've overridden invokeMethod using the 'static' qualifier and by assigning it an appropriate closure, but in addition we first look-up a MetaMethod with the line:

Code Block

def metaMethod = delegate.class.metaClass.getStaticMetaMethod(name)

A MetaMethod in Groovy is a method that is known to exist on the MetaClass whether added at runtime or whatever, thus we check if there is an existing MetaMethod and if there isn't we simply return "bar", hence the behaviour of the assert statements is correct.